十 ARM9(2440)的IIC-理论知识及程序实例

pISR_IIC = (unsigned)IicInt;
rINTMSK &= ~(BIT_IIC);

//Enable ACK, Prescaler IICCLK=PCLK/16, Enable interrupt, Transmit clock value Tx clock=IICCLK/16
// If PCLK 50.7MHz, IICCLK = 3.17MHz, Tx Clock = 0.198MHz
rIICCON = (1<7) | (0<6) | (1<5) | (0xf);
rIICADD= 0x10;//2440 slave address = [7:1] 实验中没有此语句时也没有影响，因为使用的是主机模式
rIICSTAT = 0x10;//IIC bus data output enable(Rx/Tx)
rIICLC = (1<2)|(1);// Filter enable, 15 clocks SDA output delayadded by junon
rIICDS = 0xDD;
Uart_Printf("Write test data into AT24C02n");

for(i=0;i<256;i++)//256
Wr24C080(0xa0,(U8)i,i);//向地址0--255写入数据0--255

for(i=0;i<256;i++)//256
data[i] = 0;//数组清零

Uart_Printf("Read test data from AT24C02n");

for(i=0;i<256;i++)
Rd24C080(0xa0,(U8)i,&(data[i]));//将读取的数据存入data数组

//Line changed 0 ~ f
for(i=0;i<16;i++)//打印读取的数据16
{
for(j=0;j<16;j++)
Uart_Printf("%2x ",data[i*16+j]);
Uart_Printf("n");
}
rINTMSK |= BIT_IIC;//屏蔽中断
rGPEUP= save_PE;//恢复GPE口
rGPECON = save_E;
while(1);
}

//*************************[ Wr24C080 ]****************************
void Wr24C080(U32 slvAddr,U32 addr,U8 data)//首地址内部地址数据
{
_iicMode= WRDATA;//模式标志记为WRDAT
_iicPt= 0;//指针记为0
_iicData[0]= (U8)addr;//内部地址
_iicData[1]= data;// 要写的数据
_iicDataCount = 2;

rIICDS= slvAddr;//0xa0设备地址
rIICSTAT = 0xf0;//MasTx,Start 启动发送
//Clearing the pending bit isnt needed because the pending bit has been cleared.

while(_iicDataCount!=-1);//未发送完在此等待

_iicMode = POLLACK;//发送完后下面等待应答信号ACK

while(1)
{
rIICDS= slvAddr;
_iicStatus = 0x100;
rIICSTAT= 0xf0;//MasTx,Start启动
rIICCON= 0xaf;//Resumes IIC operation. 恢复IIC总线

while(_iicStatus==0x100);//未接收到ACk在此等待

if(!(_iicStatus&0x1))
break;//When ACK is receivedACK收到后跳出循环
}
rIICSTAT = 0xd0;//Stop MasTx condition 停止信号
rIICCON= 0xaf;//Resumes IIC operation.
Delay(1);//Wait until stop condtion is in effect.恢复
//Write is completed.
}

//**********************[ Rd24C080 ] ***********************************
void Rd24C080(U32 slvAddr,U32 addr,U8 *data)//首地址 内部地址 读取的数据存入的地址
{
_iicMode= SETRDADDR;//模式设为SETRDADDR
_iicPt= 0;
_iicData[0]= (U8)addr;//_iicData[0]存内部地址
_iicDataCount = 1;//计数值

rIICDS= slvAddr;//首地址0xa0
rIICSTAT = 0xf0;//MasTx,Start启动
//Clearing the pending bit isnt needed because the pending bit has been cleared.
while(_iicDataCount!=-1);//未读取完成

_iicMode= RDDATA;//完成后进入读取数据模式
_iicPt= 0;
_iicDataCount = 1;

rIICDS= slvAddr;
rIICSTAT= 0xb0;//MasRx,Start设置为主接收模式
rIICCON= 0xaf;//Resumes IIC operation.恢复IIC总线操作
while(_iicDataCount!=-1);//读取未完成

*data = _iicData[1];//1
}

//-------------------------------------------------------------------------
void __irq IicInt(void)
{
U32 iicSt,i;

rSRCPND = BIT_IIC;//Clear pending bit
rINTPND = BIT_IIC;
iicSt= rIICSTAT;//控制状态寄存器

if(iicSt & 0x8){}//When bus arbitration is failed.总线仲裁失败执行空操作
if(iicSt & 0x4){}//When a slave address is matched with IICADD从地址匹配执行空操作
if(iicSt & 0x2){}//When a slave address is 0000000b
if(iicSt & 0x1){}//When ACK isnt received未收到应答信号执行空操作

switch(_iicMode)
{
case POLLACK:
_iicStatus = iicSt;//控制状态寄存器的值赋给_iicStatus
break;

case RDDATA:
if((_iicDataCount--)==0)
{
_iicData[_iicPt++] = rIICDS;

rIICSTAT = 0x90;//Stop MasRx condition
rIICCON= 0xaf;//Resumes IIC operation.
Delay(1);//Wait until stop condtion is in effect.
//Too long time...
//The pending bit will not be set after issuing stop condition.
break;
}
_iicData[_iicPt++] = rIICDS;//The last data has to be read with no ack.

if((_iicDataCount)==0)
rIICCON = 0x2f;//Resumes IIC operation with NOACK.第一次不产生应答信号进行第二次读取并将第二次读取的
///////////////数据存入数组中（第一次和第二次读取的数据实际一样）
else
rIICCON = 0xaf;//Resumes IIC operation with ACK
break;